Tachometer.



H. GALOPIN.

TAGHOMETER. APPLICATION FILED APR. 11 1912.

Patented Mar. 25. 1913 fiXed on one arm 4 of an angle-lever 5 ful-UNITED STATES PATENT OFFICE.

HENRI GALOPIN, OF MELBOURNE, VICTORIA, AUSTRALIA, ASSIGNOR TO JOHN NORMAN MATHESON, 0F TYEBS, AUSTRALIA, AND WILLIAM MAXWELL BRUCE, 0F

rmmepeon, AUSTRALIA.

TA'CHOMETER.

Patented Mar. 25, 1913.

Application filed April 113 1912. Serial R o. 690,131.

To all whom it may concern: Be it knownnt-hat I, HENRI GALOPIN, a

citizen of the Republic of France, residing at Temple Court Place,Melbourne, in the State of Victoria, Australia, scientific-instrumentmaker, have invented Improvements in Tachometers, ofwhich the followingis a specification.

This invention relates to tachometers used on vehicles to both indicatethe speed and record same on a diagram paper strip and the improvementsare devised for the purpose of insuring accurate results with suchinstruments.

The improvements are particularly applicable to tachometers wherein theindicating and recording mechanism is controlled by a spring loadedgovernor, the arms of which fly out with the centrifugal force and causea sleeve to slide along the governor spindle to which the motion fromthe vehicle wheel is imparted.

The drawings illustrating the invention comprise-Figure 1 being a planof the mechanism, Fig. 2 being a vertical section on line IIII of Fig.1, Figs. 3 and 4 being enlarged details of construction.

According to this invention the slidable sleeve 1 of the governor arms 2is formed with a recess with which engages a stud 3 crumed on a pivot 6.The angle-lever is provided on the other arm 7 with an adjustable pin 8adapted to engage with a double inclined. recess 9 in the indicatinglever 10, said recess being shaped so as to compensate for thedifference between the centrifugal force of the governor and theresistance of the balancing spiral spring 11 which surrounds the spindle12 thereof and bears against the slidable sleeve 1. This recess 9 in thelever is closed on the outside by an adjustable double actingspringfastened to Said lever while the inside inclined bearing face ofthe recess has at the outer end acomparatively long inclined face 14 andat the inner end a comparatively short face 15 of greater inclination.The main portion 16 of the spring has a shorter spring 17 of lesstension joined to its forward end which doubles back and bears againstthe pin 8 and'the spring is adjusted by a screw 18. By this means thepin during low speeds engages the short greater inclined bearing face15, and the weaker portion 17 of the spring thus insuring the indicatinglever responding correctly while during greater speeds the pin engagesthe longer inclined bearing face 14 and the tension is transferred tothe stronger portion 16 of the spring by reason of the weaker portionclosmgagainst it. By this means the indicating lever 10 is renderedsensitive and so responds quickly at low speeds thus overcoming thedifiiculty usually arising in tachometers and insuring accuraterecordmg. The indicating lever 10 is normally pressed backward by alight adjustable spring 19 mounted on the angle lever 5 while the doubleacting spring insures the return of said lever to zero.

The recording pen 20 is mounted on a short spring control-led lever 21fulcrumed on a pivot 22 on the lever 10 and is thereby yieldinglymounted or capable of vertical reciprocation. If it is desired that thepen.

shall be maintained in constant contact with the traveling diagram paperstrip 23 the spring 24 which controls the pen lever would be mounted onthe top of the indicator lever and bear against the underside of the leg25 of the bifurcated rear end of said pen lever. By preference howeverthe latter is constantly reciprocated vertically so as to intermittinglypress the recording pen on the diagram paper strip in order to mark asuccession of dots forming a practically continuous line, theadvantagesof which operation are that the tapping motion prevents the ink fro-mclogging at the point of the pen and there is less frictional resistancebetween the pen and the record strip. The reciprocating motion iseffected by means of a framed rocking lever 26 which has a pivotal shaft27 journaled in brackets 28 while one bar 29 of said rocking lever isin-engagement with one or more contacts on a revoluble shaft 30 of themechanism. By preference the contact consists of a'cam 31 upon whichrests a pin 32 provided on the underside of the bar 29 of said rockinglever as illustrated in Figs. 1 and 4 while in this construction thespring 24 bears against the leg 33 of the pen lever and so normallyholds the pen off the paper strip. The forward transverse rod .34 of theframed rocking lever rests on the pen lever 21 and 'sointermittinglypresses the pen, against the pressure of the spring 24, down upon thepaper strip 23 and marks a succession of dots.

The diagram paper strip travels by means of a rotating drum' 35 actuatedby clock Work 36 and is held fiat by means of a stud 36 on the undersideof the indicator lever 10 and flat springs 37 and 38.

In order to' provide against any irregularities which may happen inmanufacturing the instruments the governor arms 2 are provided-Withadjustable sliding weights 39 by means of which the range of said armsmay be increased or decreased as required.

I claim 1. In tachometers a centrifugal governor, a balancing spiralspring controlling the same, an angle-leveroperated by said governor, anindicating lever formed with a recess adapted to be engaged by a pin onsaid angle-lever, said recess being shaped so as to-compensate for thedifference between the centrifugal force of the governor and theresistance of the saidbalancing spring of the governor.

2. In tachometers a spring controlled centrifugal governor, anangle-lever operated thereby, an indicating lever formed with a doubleinclined recess adapted to be ensubstantially as and for the purposespeci- 4. In tachometers a spring controlled centrifugal governor, anangle-lever operated thereby, an indicating lever formed with a doubleinclined recess adapted to be engaged by a pin provided on saidanglelever, said recess having a double inclined bearing face inclosedby a-double acting spring substantially as and for the purposespecified.

In testimony whereof I have'hereunto set my hand in presence of twosubscribing wit nes'ses. t

, HENRI GALOPIN.

WVitnesses: Q

EDWARD N. WVATERs, WILLIAM G. HOLDEN.

